In medicine, and most particularly in the field of vascular surgery, it is often necessary to operate on vessels, for example, for the removal of calcifications from blood vessels. In making such operations, it is necessary to arrest temporarily the blood circulation through the part of the blood vessel to be treated. Normally the operation is effected in that the blood vessel is constricted by means of Pean's forceps on either side of the region to be treated, the blood vessel being then opened or cut off at the treatment region. The treatment proper is then carried out and when this is terminated the incision surfaces of the blood vessel are sutured with, for example, catgut. In order to minimize the risks associated with the arrest of the blood circulation through the vessel (hemostasis) it is important that the operation be carried out as rapidly as possible, normally within 10-15 minutes. Furthermore, the arrest of the circulation often cuts off the blood supply to important organs, such as the brain in, for example the treatment or so-called "de-coking" of the carotid artery. In this treatment, it is required that the blood circulation to the brain be cut off for at most 1-2 minutes if permanent brain damage is to be avoided. It will be appreciated that it is extremely difficult to carry out an operation of the above-mentioned type in such a short time. In order, in such cases, to give the surgeon longer time in which to work, a method has been developed according to which the carotid artery is first constricted on either side of the treatment region. A longitudinal slit is then made at the treatment region, instead of cutting off the carotid artery, as is normally the case with other blood vessels. A plastic tube is then inserted into the longitudinal slit and is disposed so that it extends beyond both ends of the slit. The artery is then fixedly clamped against the plastics tube near its ends, whereupon the constriction on either side of the treatment region is removed. As a result, a free passage for the blood circulation will be obtained at the same time as the part of the carotid artery to be treated or "de-coked" is exposed so that the surgeon is given a reasonable period of time to carry out the treatment. When the treatment has been completed, the plastic tube must be removed and the blood vessel closed. To this end the artery is once again constricted on either side of the treatment region, the forceps on the artery at the ends of the plastic tube are released, the plastic tube is taken out, the slit in the artery is sutured and finally the constriction on either side of the treatment region is removed.
Even if the above-described procedure entails substantial progress as compared with conventional surgery, it should nevertheless be observed that both the first stage with the insertion of the plastic tube and the final stage with the removal of the plastic tube and the suturing of the artery must be effected within the given time limit of 1-2 min., preferably within 1 min. Here, the initial stage is relatively rapid and offers no great problem as regards time, whereas the final stage which includes the suturing of the artery is much more time-consuming and difficult to carry out within the given period of time. The present invention obviates this problem in that the constriction of the blood circulation need only be effected in the initial stage, whereas the final stage can be carried out with uninterrupted blood circulation, that is to say the surgeon can work without being pressed for time.
In another known type of operation, a damaged part of a blood vessel is removed and replaced with an artificial graft in the form of a tube of knitted fabric manufactured from "DACRON" (polyethylene terephthalate). The graft includes a support portion which is removed once the graft has been united permanently, by healing up, to the blood vessel. This removal is effected by a further operation approximately a couple of months after the first operation when the graft was inserted. As will be explained in greater detail below, the present invention makes it possible to remove the support portion without any special operation. It will be readily observed that this entails considerable advantages.
A further type of operation in ureteritis involves the removal of a portion of the ureter, the remaining portions of the ureter being sewn together. A flexible insert of rubber is, in this case, inserted into the ureter, the element bridging the region of the suture and preventing urine from coming into contact with said region, thereby facilitating healing. However, after the healing process, the insert element must be removed, which entails a new operation. The present invention also obviates the need in this case of a subsequent operation and permits instead the removal of the insert without any special surgical procedure.
These and further advantages gained by the present invention are achieved in that the tubular insert is designed such that, when necessary, it can be divided or taken apart along a previously provided line of fracture to form a thread of a substantially smaller cross-section than that of the insert. According to the invention, the insert consists of an unperforated hollow body of substantially circular cross-section and having a spiral line of fracture running about the periphery of the body and weakening the cohesion of the body at the spiral coils for parting of the body as an elongated thread. Further characteristic features of the invention will be apparent from the appended claims.
The nature of the invention and its objects will be more fully understood from the following description of the drawings, and discussion relating thereto.